In this paper, the idle speed control problem is addressed via maximal safe set computation. A hybrid model of the engine in idle mode is used. The solution is based on the transformation of the continuous dynamics from the time-domain to the crank-angle domain and on the linearization and discretization of these dynamics. A ‡exible and portable algorithm in the discrete-time domain is proposed...

In the past, we demonstrated how fuzzy concepts can easily be used in the Johnson algorithm for managing uncertain scheduling on two-machine flow shops. This paper extends these concepts to fuzzy flow shops with more than two machines. A new fuzzy heuristic flow-shop scheduling algorithm (the fuzzy Gupta algorithm) is then designed since optimal solutions seem unnecessary for uncertain environm...

We derive estimators of throughput sensitivity to changes in buffer capacity for continuous flow models of a transfer line comprising two machines separated by a buffer of finite capacity, where machines are subject to operation-dependent failures, i.e., a machine cannot fail when it is idle. Both repair times and failure times may be general, i.e., they need not be exponentially distributed. T...

This paper addresses the gradient estimation of transfer lines comprising two machines separated by a buffer of finite capacity. A continuous flow model is considered, where machines are subject to operation-dependent failures, i.e., a machine cannot fail when it is idle. Both repair times and failure times may be general, i.e., they need not be exponentially distributed. The system is hybrid i...

Flexible flow shops are becoming increasingly common in industry practice because of higher workloads imposed by jobs on one or more stages, thus requiring two or more units of the same machine type. We present a methodology for solving this important problem, namely group scheduling, within the context of cellular manufacturing systems in order to minimize the total completion time of all grou...

The goal of this paper is to investigate scheduling heuristics to seek the minimum of a positively weighted convex sum of makespan and the number of tardy jobs in a static hybrid flow shop environment where at least one production stage is made up of unrelated parallel machines. In addition, sequence and machine dependent setup times are considered. The problem is a combinatorial optimization p...

Gündüz Ulusoy Faculty of Engineering and Natural Sciences, Sabancı University, Istanbul, Turkey. [email protected] ABSTRACT This paper considers multiprocessor task scheduling in a multistage hybrid flow-shop environment. The objective is to minimize the make-span, i.e. the completion time of all the tasks in the last stage. This problem is of practical interest in the textile and process ...

The work described in this paper attempts to validate the implicit assumption in traditional flow shop scheduling research that there is a buffer of infinite capacity between any two adjacent machines. The modified NEH (Nawaz, Encore and Ham) algorithm is used to generate an initial permutation schedule which is then improved by tabu search. For any given sequence, a limited equal buffer size i...